DTU scientists propose solution to city pollution problems

Hydrogen tablets could reduce emissions of mono-nitrogen oxides (NOx) from city buses by up to 270 tonnes a year, the engineering trade magazine Ingeniøren reports.

Practically all buses and lorries are equipped with catalytic converters that reduce the emission of the toxic NOx gasses, but a 2012 report from the International Council on Clean Transportation found that emissions were still up to four times the permitted limit.

Status quo not good enough It is now believed the catalytic converters only function properly when the exhaust fumes are over 200 degrees Celsius, which is seldom the case when the vehicle makes regular stops.

The hydrogen tablet, developed by a team from Denmark’s Technical University (DTU), could solve this problem by allowing the process to occur at lower temperatures.

Tue Johansen, the technical head of Amminex, a company that develops catalytic converters based on hydrogen tablet technology, told Ingeniøren that the technology could remove up to 300kg more NOx per bus every year (a total of 270 tonnes) if it was installed on all of Movia’s vehicles.

“All that’s required to change the existing vehicle approval rules is political will,” he said.